1. Field of the Invention
The present invention relates to a camera, particularly to a camera having a focal plane shutter in which the shutter is driven by an electromagnetic driving source.
2. Description of the Prior Art
Heretofore, running of shutter screens in a camera has been done by a mechanical driving source such as a spring, or the like. On the other hand, recently use of electronics in a camera has advanced and there has been a tendency to electrically control an exposure and a photographing sequence, etc. Therefore, since a driving system for a shutter has a mechanical arrangement even in a camera which has advanced electronics technology employed therein, there has been the shortcoming of having a complicated arrangement for the total camera. Thus quite recently a camera having an electromagnetic driving source in which a running of a shutter screen is made directly by electromagnetic power has been proposed.
However, when a motor is used as an electromagnetic driving source, it is difficult to use a large size motor because of a limited space available within a camera for housing the same.
When a focal plane shutter having a leading blade group and a rear blade group each of which consists of a plurality of divided blades (for example, as disclosed in U.S. Pat. No. 4,024,555) is used, it is desirable to place a motor at a side of an exposure aperture opening in such a manner that a shaft of the motor is perpendicular to the film plane.
In a generally known type of a single lens reflex camera using a 35 mm film, a sprocket is provided between a mirror box and a wind up shaft as shown in FIG. 1, and a distance between the sprocket and the mirror box needs to be extended in order to house a motor within said space, but it makes a lengthwise dimension of the camera longer, which is not desirable. Therefore, a motor is placed between the sprocket and a front plate of the camera, and in this case the distance between the front plate and a partition wall of a sprocket part is short. Therefore, a height of a motor, that is, its dimension in its axial direction, needs to be made small.